Re: icmp_route_lookup returns wrong source address information
From: David Miller <davem@davemloft.net>
Date: 2011-07-22 13:23:07
Subsystem:
networking [general], networking [ipv4/ipv6], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, David Ahern, Ido Schimmel, Linus Torvalds
From: Florian Westphal <fw@strlen.de> Date: Wed, 20 Jul 2011 21:22:58 +0200
Problem is that xfrm_decode_session_reverse() may rebuild fl4 from scratch. In my setup, "goto relookup_failed" will be hit a bit later on, and fl4->saddr will be set to iph->daddr...
Indeed, we can't use this new fl4 until we commit to using 'rt2'. Please give this patch a try: -------------------- icmp: Fix regression in nexthop resolution during replies. icmp_route_lookup() uses the wrong flow parameters if the reverse session route lookup isn't used. So do not commit to the re-decoded flow until we actually make a final decision to use a real route saved in 'rt2'. Reported-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net> --- net/ipv4/icmp.c | 14 ++++++++------ 1 files changed, 8 insertions(+), 6 deletions(-)
diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index 5395e45..23ef31b 100644
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c@@ -380,6 +380,7 @@ static struct rtable *icmp_route_lookup(struct net *net, struct icmp_bxm *param) { struct rtable *rt, *rt2; + struct flowi4 fl4_dec; int err; memset(fl4, 0, sizeof(*fl4));
@@ -408,19 +409,19 @@ static struct rtable *icmp_route_lookup(struct net *net, } else return rt; - err = xfrm_decode_session_reverse(skb_in, flowi4_to_flowi(fl4), AF_INET); + err = xfrm_decode_session_reverse(skb_in, flowi4_to_flowi(&fl4_dec), AF_INET); if (err) goto relookup_failed; - if (inet_addr_type(net, fl4->saddr) == RTN_LOCAL) { - rt2 = __ip_route_output_key(net, fl4); + if (inet_addr_type(net, fl4_dec.saddr) == RTN_LOCAL) { + rt2 = __ip_route_output_key(net, &fl4_dec); if (IS_ERR(rt2)) err = PTR_ERR(rt2); } else { struct flowi4 fl4_2 = {}; unsigned long orefdst; - fl4_2.daddr = fl4->saddr; + fl4_2.daddr = fl4_dec.saddr; rt2 = ip_route_output_key(net, &fl4_2); if (IS_ERR(rt2)) { err = PTR_ERR(rt2);
@@ -428,7 +429,7 @@ static struct rtable *icmp_route_lookup(struct net *net, } /* Ugh! */ orefdst = skb_in->_skb_refdst; /* save old refdst */ - err = ip_route_input(skb_in, fl4->daddr, fl4->saddr, + err = ip_route_input(skb_in, fl4_dec.daddr, fl4_dec.saddr, RT_TOS(tos), rt2->dst.dev); dst_release(&rt2->dst);
@@ -440,10 +441,11 @@ static struct rtable *icmp_route_lookup(struct net *net, goto relookup_failed; rt2 = (struct rtable *) xfrm_lookup(net, &rt2->dst, - flowi4_to_flowi(fl4), NULL, + flowi4_to_flowi(&fl4_dec), NULL, XFRM_LOOKUP_ICMP); if (!IS_ERR(rt2)) { dst_release(&rt->dst); + memcpy(fl4, &fl4_dec, sizeof(*fl4)); rt = rt2; } else if (PTR_ERR(rt2) == -EPERM) { if (rt)
--
1.7.6